Also, The camera came with a Sigma 70-300mmD 4-5.6DG. This lens is really performing well. It appears to be an early version and I cannot find an earlier users manual on this lens which will tell me what the little switch (pictured below) is. It has two positions, one reveals the red dot. Any info is appreciated.http://www.flickr.com/photos/41610922@N04/9802850675/

The switch in the image is the Aperture Ring Lock switch.Set the Aperture to the minimum opening (largest f/#) then lock the aperture ring. On Nikon DSLR's the aperture is changed by rotating the sub-command dial (finger wheel) or command dial (thumb wheel) which makes the aperture ring redundant.

as others said it's the ring lock. if you don't lock it, you might inadvertantly move the ring to a smaller aperature, adn the camera will display FEE on the top lcd. just rotete it back and it will correct itself

The others have mentioned the aperture but I have to say I would be very concerned about a camera where the screws looked like that - clearly someone who did not know what they were doing was working on it. I would send it in for a thorough inspection and cleaning and ask to have all the screws replaced.